Molding machine



0d. 6, 1942- R. w. DlNzl.

MOLDING MACHINE Filed July 3l, 1940 2 shteecs-Sheel l ATTORNEY Oct. 6, 1942. R. 5w. DlNzl. '2,298,044

MOLDING MACHINE Filed July C51, 194C 2 Sheets-Sheel 2 mvENToR @www5/l. @f1/24 ATTORNEY Patented Oct. 6, 1942 UNITED STATES' 2.298.044 Momma manina Rionero w. ninnl, Westfield, N. J., signor to The Watson-Stillman Co., Roselle, N. J., a corporation of New Jersey Application July 31,1940, serial No. 348,619 A ."lclaims.

An important -object of the present invention is to provide improved means for adjusting the stroke length of a platen and for timing the operation of an ejector mechanism with ation to the stroke adjustment in a molding machine having a platen shiftable toward and from a companion platen to close and open a mold andeject the molded product."

Other objects of the invention will appear Y points in their length said rods have keeper abuthereinafter.

In the drawings, Fig. 1 is a longitudinal sectional view of a portion of an injection molding machine embodying the invention;

Fig. 2 is a diagrammatic view oi part of a conf trol system for the machine;` Fig. 3 is a horizontal section taken centrally through the platens and dies of the machine, with the dies in closed relation, and showing part of the mechanism for ejecting castings; Fig. 4 is an enlarged. vertical cross lsection approximately on'the line I-,4 o! Fig. 1; and Fig. 5 is a sectional side elevation of`a portion of the machine showing the means for controlling the stroke length 'of the sliiftable platen and the operation of the ejector mechanism.

The invention is shown as embodied in an .injection molding machine of the type disclosed in al copending patent application of EdwardR.

` .Knowles Serial No. 204,122 led April 20, 1938.

The machine includes a basel upon which are mounted two opposed platens 2 and 3. Platen 2 bears a die or mold section D and platen 3 -bears a companion die or mold section D'. Associated with platen 3, and supported in a fixed position, by means not shown, there is a heating cylinder 4 for thermoplastic material to be molded. An injection plunger 5, indicated by dotted lines, is reciprocable within the cylinder., and the cylinder has aninjection nozzle 6 at its forward end to discharge into a mold-charging port or gate I of the die D'. Platen 3 is mounted for limited reciprocation sumcient only to make and break contact between saidnozzle and mold gate. Platen 2 is mounted for more extended reciprocation to close and open the mold by moving the.

die D toward and from the die D'.

o For reciprocation of the platen 2 there is a hydraulically op erated mechanism including a cylinder 8. mounted upon the base in horizontal alinement with the centers of the platens. A ram 9 is reciprocable within Athe cylinder and has its forward end operatively connected to a yoke lo. The letter-1s mounted to sudo between guide extensions Il borne by the platen 2. Locking wedges or bolts are mounted upon the rear face o1 platen 2 for sliding"transversely of the direction of movement of the platen. One of thesebolts is shown at I2 in Fig. l. The yoke 5 is operatively connected to the joint of a toggle I3 whose opposite ends are operatively connected to said bolts. Platen I has parallel resistance rods Il lanchored thereto and extending through bushings I5 borne by platen 2. At intermediate ments `I6 located s0 that the locking bolts can engage them when the platen 2 has been ad vanced along the rods sufciently to bring the die D only a. short distance from the die D'. During said preliminary advance the outer ends of the lockim bolts ridealong the strain rods and the toggle is thereby prevented from expanding under the thrust of the ram 9. Consequently the yoke, the toggle. the locking bolts and the platen 2 will advance at the same rate as the ram until bolts into engagement with the keeper abutments. The bolts and keeper abutments are formed for wedging coaction-to complete the advance of the platen 2 and finally lock it in a position to' hold the die D pressed against the die D'. The mold is thus closed and locked in preparation 'for receiving an injection charge from the cylinder l. Upon retraction of the ram the toggle causes retraction of the bolts from the keeper abutments and then theyoke, the toggle, the lockingbolts, the platen 2 and the die D are drawn back as a unit by the ram to open the mold. The

lockirm mechanismis not illustrated in detail in this application bt is fullydisclosedin the afore-y saidv copending application.

In orderto save power and also save time in the operation o! the machine, it isdesirable to limit the retraction of the platen 2 from the platen 2 to ahdistance just suillcient-for free ejection of the casting or castings from the opened mold. That distance will, of course. vary with dies o! diierent thicknesses and castings of ditter' ent sizes and shapes. The'present invention isdirected primarily to a more convenient adjustment o! both the stroke of the platen 2 and the timing of the ejection` in accordance with the VThere is provided an ejector mechanism including a plunger I1 mounted for horizontal reciprocation in acentral bore Il in the platen and having rack teeth- Il at its under side. Bore I8 55.- opens into a recess 20 in the adjacent face of the from said recess and having a reduced portion 22 opening through the forward face of the die. A

block 28 is reciprocable within the said recess and bears a central knock-out pin 24 protruding into the bore 2| and having a reduced forward portion projecting into the reduced portion 22 of the bore. Smaller knock-out pins 25 are also borne by the block in positions spaced outwardly from the central pin and extend forwardly through bores in the die D. The length of all of.l the knock-out pins is such that when the block headed screws 5|. These are passed through slots 42 in the plate 58 and screwed into said margin. 'I'he slots enable adjustment of the plate in the bracket. Said plate has a straight,

is back against the face of the platen the forward ends of the pins will be inward of the forward face of the die. The central pin also protrudes rearward from the block into the bore I8 so that when the plunger I1 is advanced it will strike said pin and shift the block and all of the,

pins forwardly to knock castings from the die.

Below the bore |8 the platen 2 has a recess 28 shaft 28 mounted in opposite walls of the recess. Said pinion meshes with the teeth of the ejector plunger |1. A driving gear 28, also within said recess, meshes with pinion 21 and is fixed to a transverse rock shaft 88. The latter extends through a bore 8| in the platen and protrudes from an outer side face of the platen. Bushings 82 fitted within opposite ends of bore 8| provide bearings for the shaft. A crank arm 88 is aflixed to the outer end of the shaft and bears a roller 84. Between the bushings 82 a torsion spring 85 encircles the shaft and has one end secured to the shaft and the other end secured to one of the bushings. 'I'his spring constantly urges the shaft rotatively to swing the crank arm counterin which there is an idler pinion 21 borne by a` horizontal lower edge 58 .and edges 54 and 55 sloping upward and outward from edge 58. 'Ihis cam plate is disposed for operation upon the roller 48 of the switch crank 42 as the platen 2 is moved.

'I'he stroke-limiting switch 4| is part of a control system for the ram 9.. A conventionalicontrol system is shown diagrammatically in Fig. 2. It includes a double-headed piston valve 56 reciprocable withina casing bore 51. When said valve is in its left-hand position, with reference to Fig. 2, it opens communication between a hydraulic pressure supply pipe 58 and a pipe 59 leading to the outer end of cylinder 48. At the same time the valve opens communication between a pipe 88, leading from the inner end of cylinder'8, andl an exhaust pipe 8|. 'I'he ram is 'then advanced to close and lock the mold. The

Y and de-energization of the solenoid 82 and said clockwise, with reference to Fig.v 5, and retract materiali length and a' sloping upper cam edge 48 leading from said abrupt edge to said track edge.

Said cam edges 88 and 48 are disposed within the path of movement of the roller 84 on the crank arm 88 as the platen 2 is reciprocated. The cam plate has a lower margin extending below the plate 88 and upon said margin there is secured a stroke-control switch 4 I. operating crank arm 42 bearing a roller 48. 'I'he cam plate is slidabiy adjustable along the plate 88 and has a guide flange 44 `slidably fitting in a groove 45 in the upper edge of plate 88. For securing the cam plate in different adjustments the plate 88 is provided with a row of screw-threaded holes 48 and the cam plate is provided with spaced slots 41 to aline with said holes. Headed clamping screws 48 are passed through said slots and screwed into selected ones of the holes to hold the plate in an adjusted position. vThe spacing of the holes provides for approximate preliminary adjustment of the cam plate, and the slots provide for accurate ilnal adjustment.

Secured to the platen 2, at'the same side of the ,machine as the cam plate 81, there is aybracket 48 in the form of a shield extending downward over the outer end of shaft 88 and its crank arm 88.. A cam plate 58 is secured in a vertical plane- Said switch has an' tion will occur just Ito the lower margin of the bracket by means of 7 5 switch is in turn subject to control by the platen 24 acting upon the switch through the cam plate 58. A spring 88 urges switch 4| to open position in which position the roller 48 is in the path of cam 58. When, however, the platen 2 is retracted to open the mold the cam edge 54 acts upon the roller 48 to swing the arm 42 and close the switch 4|. A circuit is thereby established including a line wire L, a conductor 81, a conductor 88, the timer 85, a conductor 88 and line wire L. Thereby the timer is put into action to close a switch' 18.

Said switch closes a circuit for the solenoid 82' including line wire L, a` conductor 1| a conductor 12 and a conductor 18. Thereby the solenoid is energized and shifts valve 58 to'its left-hand position to cause advance ofthe ram to close and lock the mold.. The timer `holds the solenoid circuit closed for a suitable period and then shifts switch 18 to break the circuit. Spring 88 then shifts valve 58 to its opposite position for retraction of the cam to open the mold. Retraction'oi' the platen 2 causes the cam 58 to close switch 4| and cause another cycle of operation.

As the platen 2 is retracted it not only causes' operation of the switch 4| to limit the stroke'but also causes operation of the ejector mechanism to strip the castings from the die D. As the platen is moved back the roller 84 of the ejector mechanism, traveling with the platen, engages rst the edge 88 and next the edge 48 of cam 81 to thereby rock the crank arm 88 and the shaft 88 to operate the gearing,th`e plunger' |1 and the knockout-pins to cause ejection of the castings. Theparts are so related that the ejecbefore the platen 2 comes to a stop.` 1

The ejectorf-.controlling cam 81 and the strokecontrolling'f'switch 4| are embodied in a unit. By

merely adjusting this unit along the fixedv plate 88, as previously described, the stroke length of the platen 2 may be varied by varyingv th'e point at which the cam 58, borne by the platen, will engage and operate the stroke-control switch 4l. At the same time such adjustment of the unit automatically accommodates the operation of the ejector mechanism to the stroke adjustment since the ejector-operating cam 31 is adjusted along with the stroke-control switch Il.

What I claim is:

1. In a molding machine, the combination ot two die-supporting platens, one of said platens being shiftably mounted, power meansy for ads i tion, said power control means including a rockvancing the shiftable platen ,toward and-retracting it from the other platen, an ejector device and operating means for said device, a unit comprisingabody.acambornebysaidbodyina fixed position thereon and an electric switch for i5 control of said power means also borne by said body andsecured .in a fixed position thereon and including a shiftable operating member; a nxed support for said unit supporting the latter for adjustment along the line of said platen advance and retraction and having a row of apertures extending along said line: fastening means selectively engageable with' said apertures for apyproximate adjustment 'and securement` of the unit at ldiilerent'positions along said line, the 25 adjustment of the unit adjusting said cam and switch in unison and to the same degree along said line; means rendering said unit adjustable along said line relatively to said fastening means for finer adjustment of the unit; and a trip 30 mounted to travel with said shiftable platen, said ejector-operating means being engageable with said cam of the unit and operable thereby',upon said platen retraction, to cause ejection of a casting from a die supported by one of said platens, said ,trip being engageable withsaid switch-operating member to operate sthe switch upon said platen retraction, for limiting retraction, and the adjustment of said unit determining said limit and timing the occin'rence of said 40 ejection. 4

2. In a molding machine, the combination of two die-supporting platens one mounted for shifting toward andv retraction from the other,

power means for advancing and retracting said shiftable platen, an ejector device, operating means for said device, a unit comprising a support, a power control means and a trip carried by said support and secured against displacement relatively to each other in the direction of said 5 platen advance and retractio means for adjustv ing and securing-said unit at anyone of a plurality of selected positionsalong the line of said platen advance and retraction vto thereby shift 'travel with said sniftabie pieten, said ejectoroperating means being engageable with said rst mentioned trip and operable thereby upon said platen retraction to a predetermined point to shifting towardand retraction from the other, power means for advancing and retracting said shiftable platen, ejector means mounted to travel with said shiftable platen, a rockable operating device for said ejector means also mountedto travel with said shiftable platen, a unit comprising a support carrying a cam and. a power control means secured to the support against displacement relatively to the cam in the direction of said platen advance and retracsame extent, and a second cam mounted to travel with said shiftable vplaten and operate said rockable power control device by platen retraction to a predetermined point to limit the said retraction, said rockable ejector-operating. device'being w operable by said ilrst mentioned cam of the unit by platen retraction to a predetermined point to cause ejection of a casting from' a die supported by one of the platens, and the adjustment of said unit timing the occurrence of said ejection and determining the limit of said retraction.

4. In a molding machine, the combination of two die-supporting platens one mounted for shifting toward an retraction from the other,

power means for advancing and retracting said shiftable platen, an ejector mounted to travel 4 with said shiftable platen, mechanism for operating said ejector borne by said shiftable platen and comprising a plunger advanceable to shift the ejector to operative position, a rock shaft, gearing operatively connecting said shaft to the plunger to reciprocate the latter by rocking the shaft, a crank arm borne by said shaft and spring means constantly urging the shaft for retraction of the plunger; a unit comprising a support, a cam and va 'power control means secured to said support against displacement relatively to each other in the direction of the said platen advance` and retraction, said vpower control means including a rockable operating device therefor; means to adjust and secure said unit at any one of a plurality of selected positions along lthe line of said platen ,travel to'thereby adjust said cam and power control means along said line in unison and to the same extent, and a cam mounted to travel with said shiftable platen and adapted topperate said rockable power control device at a predetermined point in said y platen retraction to limit the' platen retraction,

said crank arm being operable by said cam carried by the unit and at a predetermined point in said platen retraction to rock said shaft and move said plunger and ejector against the resistance of said spring means for ejection of a casting from a die supported by the said shiftable platen, and the adjustment of said u nit timing f the occurrence of said ejection in the platen re'-l traction and determining the limit of said replaten stroke. and the adjustment of said unit two die-supporting platens one by one of the said platens. SII-ld 00nd mi bei mman,

engageable with said power control means to operste the latter upon a predetermined limit of said platen retraction and thereby' limit the 5. In `a molding machine, the combination of two die-,supporting platens one mounted for f shifting towarrand retraction from the other, n

e tu c ming power me ,L advancing andretracting said gieierolilsicnuirli'nsceldolfiiidot eljeectionoxvgeby .me 70.. shiftable i;l', an ejector device carried by said um relation of the platen stroke mit and thev l shiftable platen, operating means for said device ejection operation will be maintained. in all ads also carried by said shiftable platen, a unit comjustments of .the said unit. L Ffm WWTF WW html means "Qd an.

.s. m a molding machine, the combination lof ejector-operating trip secured to lsai'd support mounted for against displacement frelativelyf to each other in the direction of said platen advance and retraction, means for adjusting said unit along the line of said platen advance and retraction, to thereby adjust said power control means and trip along said line in unison and to the same extent while maintaining them in their ilxed positions with relation to each other, and a power control trip mounted to travel with said shiftable platen, said ejector-operating means being engageable with said ejector-operating trip and operable thereby upon said platen retraction to a predetermined point to cause ejection of al casting from a die supported by the shii'table platen, said power control trip being engageabie with said power control means to operate the latter upon said platen retraction to a predetermined point, whereby the adjustment of said unit determines the limit of platen retraction and the occurrence of said ejection while maintaining the timed relation of the platen stroke limit and the ejection operation in all adjustments of the said unit.

6. In a molding machine, the combination oi' two die-supporting platens one of said platens being shiftably mounted, power means for advancing the shiftable platen toward and retracting it from the other platen, an ejector device and operating means for said device, a unit comprising a body, a cam borne by said body in a iixed position thereon and an electric switch for control of said power means also borne by said body and secured in a ilxed position thereon and including a shiftable operating member, a iixed support for said unit, means for adjusting said unit on said support along theline of said platen advance and retraction, the adjustment of the unit shifting said-cam and switch in unison and to the same extent along said line, and a trip mounted to travel with said shiitable platen, said ejector-operating means beingV engageable with said cam of the unit and operable thereby upon said platen retraction to` cause ejection o! a casting from a die supported by o ne of said platents, said trip being engageable with said switch-operating member to operate the switch upon said platen retraction for limitingretraction, and the adjustment of said unit determining said limit and timing the occurrence of said ejection,

'1. In a molding machine, the combination of two die-supporting platens one of said platens being shiftably mounted, power means for advancing the shiitable platen toward and retracting it from the other platen, an ejector device and operating means therefor carried by the shii'table platen, a unit comprising a body, a cam borne by said body in a. xed position thereon, an electric switch for control oi said power means also borne by said'body and secured in a iixed position thereon and including a shiftable operating member, a tlxed support for said unit, means for adjusting said unit on said support along the line of said platen advance and retraction. the adjustment of the unit shitting said cam and switch in unison and to the same extent along said line while maintaining them in their ilxed positions with relation to each other, and a switch-operating trip mounted to travel with said shiitable platen, said ejector-means being engageable with said cam of the unit and operable thereby upon said platen retraction to cause ejection of a casting from a die -supported by said shiftable platen, and said trip being engageable with said switch-operatingmember to operate the switch upon said platen retraction for limiting said retraction, and the adjustment of said unit determining said limit and timing the occurence of said ejection.

' RICHARD W. DINZL. 

